As many electric products have been electronically controlled, circuit boards supporting such electronic control are also increasingly used for more various products recently. A flexible print circuit board as one of the circuit boards is a circuit board formed by attaching a plastic film of polyimide and the like to a metal such as a copper foil. The flexible print circuit board is exposed to relatively high temperatures. Therefore, heat resistance as well as excellent adhesion property is required for an adhesive composition used for formation of the circuit board.
An acrylic resin, a polyester resin, a rubber-epoxy resin and the like have been conventionally used as the adhesive composition for the flexible print circuit board. Such an adhesive composition is insufficient in solder reflow required for the adhesive composition for the flexible print circuit board because the resin itself used in the composition has low heat resistance. With the problem, adhesive compositions prepared using an aromatic polyamide resin, an aromatic polyimide resin, or the like, which has relatively high heat resistance, have been used recently. However, in such adhesive compositions prepared using an aromatic polyamide resin, an aromatic polyimide resin, or the like in view of the heat resistance, the resin itself has high hygroscopicity. Therefore, absorbent moisture in the adhesive compositions is heated at the time of soldering, and thereby adhesive agents possibly generate blister, resulting in deterioration of adhesive force.
With respect to a resin composition which can be used for such adhesive compositions, Japanese Kokai Publication No. 2003-183495 disclosed is a fluorine compound-containing resin composition containing fluorine-containing poly(ether keton) s and/or poly (ether nitrile) s, and an epoxy resin and/or a phenol resin at a specific compounding ratio. However, the resin composition has room for improvement such that the resin composition has more improved adhesion property to a base material without decrease in heat resistance and can be a resin composition for providing an adhesive composition preferably used to various base materials.